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seagreen_turtle

Help w/ diagnosing sudden huge spike in steam heat - broken thermostat

I'm hoping someone could make an educated guess about what's happening with my steam/boiler heating system. I came home from work to discover a very hot house and that distinctive hissing sound from radiators that you might hear if you turn the thermostat very high. I was pretty mystified because 1) it's been cold enough the past week or so that the heat has been on but definitely not hot (I keep the house on the cooler side in fall/winter/spring (68 degrees), 2) I haven't touched the thermostat in over a week, and I don't like to ever crank it up because I worry (maybe unnecessarily) that something might break.


My house is 100 years old. The furnace was put in in 2001. It's been serviced since of course. The thermostat's display is a screen with black numerals but the side that shows the setting only displays if I actually change it. It disappears in a few seconds after that. Does this part about the display sound like a need a new battery? I'm not so concerned about this right now unless it's related to why the furnace is on "runaway" mode.I kept adjusting it lower but the heat/steam continued to be on high. Finally I turned the heat on/off slide to off.


Money is really tight for the next couple of weeks so I hate to call someone out who will charge me hundreds just to look at it.

Any guess anyone? Clearly I don't have any experience with HVAC repair. Thanks for reading this.



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